Composition of organic gel formulations for isolation of high temperature and salinity petroleum reservoir zones

ABSTRACT

This disclosure relates to an organic gel formulation composition for blocking fluids in naturally fractured carbonate reservoirs, for salinity conditions up to 31,870.50 ppm of total dissolved solids and temperatures up to 120° C., that is, for the purpose temporarily isolating areas of the reservoirs, that will be treated with chemical and radioactive products to quantify the oil remaining in them, the stability of the gel is controlled in a certain period of time, through the synergic effect of the supramolecular interaction between the components of the gel formulation. A disclosed composition may include 0.3 to 1% by weight of a copolymer of acrylamide butyl tertiary of sulfonic acid and acrylamide, and 0.12 to 0.4% by weight of phenol and from 0.18 to 0.6% by weight of hexamethylenetetramine.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Mexican Patent Application No.MX/a/2018/009309, filed Jul. 31, 2018, the entire contents of which isincorporated herein by reference.

FIELD OF INVENTION

This disclosure describes an organic gel formulation composition for theblocking of naturally fractured carbonate reservoir fluids at salinityconditions up to 31,870.50 ppm of total dissolved solids andtemperatures until 120° C., that is in order to temporally isolatereservoir areas that will be treated with chemical and radioactiveproducts for quantification of remaining oil in them, the stability ofthe gel is controlled in a certain period of time, through the synergiceffect of the supramolecular interaction between the components of thegel formulation.

BACKGROUND

A gel is a colloidal system where the continuous phase is solid, and thedispersed phase is liquid. The gels have a similar density to liquids;however, their structure resembles much more solids. The most commonexample of gel is edible gelatin. They have a wide application field atindustrial level. In oil industry, the use of gels has been extended tonaturally fractured reservoirs and its main application has been inconformance control, enhanced recovery processes, as well aspermeability modifiers, such as diverging, fracture sealants forhydraulic fracturing and as isolators. In these applications, thestability of the gel plays an extremely important role and it depends onthe chemical structure of the gel, in addition to the conditions oftemperature, pressure and salinity that are held in the reservoir.

Nowadays, the use of polymer-based gels is one of the main techniqueswithin of chemical methods used in the oil industry. Most gels reportedin literature are polyacrylamide base or acrylamide-based copolymerswith inorganic or organic cross-linkers such as Cr (III) (i), Al (III)salts, among others, used to form an inorganically cross-linked gelledsystem; these gels are the result of the ionic bond between thenegatively charged carboxylate groups and the positive charge of thepolyvalent ions (ii). However, the formation time of the most usedgelled systems such as chromium (III) acetate/partially hydrolyzedpolyacrylamide (PHPAM) is approximately only 5 hours at 40° C., which isinsufficient to place the gel in the bottom of the formation in wellswith too deep production intervals. Procedures have been reported toincrease gel formation time by using stronger cross linkers such asmalonate and glycolate (iii) anions, to make their placement possible,however, the loss of consistency could also occur when the binding withCr (III)) becomes too strong, in addition to the ionic bonds beingunstable at temperatures higher than 70° C. (iv).

Organic cross-linkers have been used to obtain gels that are stable inreservoirs with a temperature range greater than 90° C., however, attemperatures above 100° C., the polyacrylamide base polymers presenthydrolysis as a consequence of the oxidative degradation of the polymerchains (v), this coupled with the presence of polyvalent ions in themedium, promotes the expulsion of water from the structure of the gel,which is known as syneresis.

Unlike inorganic cross-linkers, the gelation mechanism of organiccross-linkers is through covalent bonds, which are by far more stablethan the ionic bond. Acrylamide base copolymers with organiccrosslinking agents, such as phenol formaldehyde, can be used to form agel with thermal stability and adjustable gelation time (vi), howeverthere is controversy regarding its toxicity. Hardy and others report theuse of a system of low toxicity formed by a copolymer of acrylamide andterbutil acrylate (PAtBA), with polyethyleneimine (PEI) as a crosslinking agent, it is stable at high temperatures, however there areserious complications in its placement and use due mainly to its rapidcross linking kinetics that in a certain proportion can be controlledwith the use of salts that provide the medium with monovalent ions thatretard crosslinking, as well as its consistency too rigid, besides beingprohibitive due to the high cost of the cross linker (vii)(viii). Amongthe most recently used methods is the secondary cross linking method,which can also increase gel strength and improve its strength, usingmore than one crosslinking agent acting in a first stage to facilitatethe placement of the system and subsequently the second cross linker,will give the definitive consistency at the bottom of naturallyfractured reservoirs (ix).

As it has been shown, the treatment with gelling polymeric systems hasbeen widely implemented to improve the efficiency of volumetric sweepingin reservoirs or to reduce the excessive water production, among others.

The patents recognized by the applicant, which protect the main chemicalfamilies of the materials used to generate the gel and the userespectively, are:

-   a) U.S. Pat. No. 5,905,100 describes the gelation of acrylamide    contained in a polymer with hexamethylenetetramine and an    aminobenzoic acid or phenol compound, as a permeability reducer.    Ahmad Morandi—Araghi., relates the gelation of a water-soluble    polymer with an organic cross-linking agent used in hydrocarbon    field operations. It provides a less toxic environment in its system    of cross-linking, reducing permeability at high temperature of    formation, by use of a system formed by a noble cross-linker and a    water-soluble polymer, composed of hexamethylenetetramine, a    cross-linker, aminobenzoic acid and phenol and an water-soluble    acrylamide polymer.-   b) U.S. Pat. No. 6,465,397 B1 refers to solutions of water-soluble    copolymers used to modify the permeability of water in    hydrocarbon-producing underground formations. The copolymer includes    copolymerized synthetic cross-linker, which has an intra and inter    molecular balance, which can be injected. Being a homogeneous    aqueous solution of copolymerized amide acrylic and a vinyl    sulfonated co-monomer and a quantity of non-ionic cross-linker.-   c) In U.S. Pat. 4507440, Friedrich Engelhardt, Steffen Piesch,    Juiane Balzer, and Jeffery C. Dawson discuss the water-soluble    polymers used in the improved oil recovery, which are cross-linked    by adding an acid. These polymers are used in acid stimulations in    oil and gas reservoirs. The polymers contain co-polymerized    acrylamide and co-monomers of the formyl-amido type. The content of    HCl in the mixture of the water-soluble copolymer such as the    copolymer 2-acrylamido-2-methylpropanesulfonic    acid-acrylamido-N-vinyl-N-methylacetamide and another as the    copolymer acrylic acid-vinyl formamido-vinyl pyrrolidone. The    cross-linked gels are stable on days at 20-30° C. in an acid medium    but there are easily hydrolyzed at 80-90° C.-   d) In U.S. Pat. No. 4,718,491, Norbert Kholer talks about the use of    polysaccharides, which are difficult to inject into porous spaces to    slow or reduce the water inflow, but they allow an incomplete    exploitation in the oil reservoirs. Its effect is lost at high    temperatures.-   e) In US patent U.S. Pat. No. 4,095,651, Guy Chauveteau discusses    the use of hydrolyzed polyacrylamide. In this type of polymers, it    is more effective for water with low salt content, degrading rapidly    with the increase of salts, with the presence of polyvalent ions,    these polymers have a tendency to form precipitates at high    temperatures that can close the pores of the formation rocks.-   f) Patent EP 2,126,016 A2 mentions an aqueous base insulating fluid    comprising an aqueous base fluid, a water miscible organic liquid    and a synthetic polymer, optionally a crosslinking agent is added to    the mixture comprising the synthetic polymer to crosslink the same,    the mixture comprising the synthetic polymer can be placed in a    selected location, allowing the mixture comprising the synthetic    polymer is activated to form a gel there.

In none of the aforementioned references is claimed, the development ofcomposition of organic gel formulations for the blocking of fluids innaturally fractured carbonate reservoirs, for salinity conditions up to31,870.50 ppm of total dissolved solids and temperatures up to 120° C.,in order to isolate temporarily zones of reservoirs that will be treatedwith chemical and radioactive products in order to quantify the oilremaining in them.

It is, therefore, the object of the this disclosure to provide acomposition of high temperature and salinity organic gel formulationsfor isolating oil reservoir zones. This disclosure relates to theformulation of two organic insulating fluids for temporary blockage innaturally fractured carbonates reservoirs, for salinity conditions(31,870.50 ppm of total dissolved solids) and temperature (120° C.), inorder to control the stability of the gel in a certain period of time(considering 24 hours of placement, 8 weeks of permanence tosubsequently degrade), through the synergistic effect of the organiccross-linking interaction between the components of the formulation, inorder to isolate an area from the reservoir rock for a control volumeinjection.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to have a greater understanding regarding the composition ofhigh temperature and salinity organic gel formulations to isolate oilreservoirs zones of the present disclosure, the following, the contentsof the accompanying drawings are briefly described:

FIG. 1 shows the resistance to inversion of the formulation described inExample 1 at 120° C. as a function of time, according to the descriptiondeveloped by Robert Sydanks (1988).

FIG. 2 Illustrates the resistance to inversion of the formulationdescribed in Example 2 at 120° C. as a function of time, according tothe description developed by Robert Sydanks (1988).

FIG. 3 shows a graph of the behavior of the viscosity with respect tothe shear rate for the formulation of Example 1 at 21° C.

FIG. 4 shows a graph of the behavior of the shear stress with respect tothe shear rate for the formulation of Example 1 at 21° C.

FIG. 5 shows a graph of the behavior of the viscosity with respect tothe shear rate for the formulation of Example 2 at 21° C.

FIG. 6 shows a graph of the behavior of the shear stress with respect tothe shear rate for the formulation of Example 2 at 21° C.

FIG. 7 shows a diagram of the viscosity measuring equipment for thedetermination of the rheological model.

FIG. 8 illustrates the Rheological model of the gellant formulationdescribed in Example 1 for shear rate ranges from 10 to 70 [1/s].

FIG. 9 shows the Rheological model of the gelling formulation, of theformulation described in example 1 for shear rate ranges from 600 to1000 [1/s].

FIG. 10 shows flow curves at different residence times of theformulation described in example 1.

FIG. 11 shows viscosity curves at different residence times of theformulation described in example 1.

FIG. 12 presents a graph of the elastic modulus versus time of theformulation described in example 1.

FIG. 13 presents a graph of the viscous modulus versus time of theformulation described in example 1.

FIG. 14 illustrates a graph of Damping factor versus time of theformulation described in example 1.

FIG. 15 shows flow curves at different residence times of theformulation described in example 2.

FIG. 16 shows viscosity curves at different residence times of theformulation described in example 2.

FIG. 17 presents a graph of the elastic modulus versus time of theformulation described in example 2.

FIG. 18 presents a graph of the viscous modulus versus time of theformulation described in example 2.

FIG. 19 illustrates a graph of Damping factor versus time of theformulation described in example 2.

FIG. 20 illustrates a comparative graph of the investment resistance ofthe formulations described in Example 1 and Example 2 at differentsalinities.

DETAILED DESCRIPTION

This disclosure relates to a composition of organic gel formulations forthe blocking of fluids in carbonated naturally fracture reservoirs,having a stabilizing effect for a gelation system at high temperature of120° C. and 31,870.5 ppm dissolved total solids of salinity as NaCI,this gelation system to serve as a barrier between the formation waterand injected fluid, in order to isolate the reservoir zone andfacilitate the quantification of the remaining oil by use of tracers incarbonated naturally fracture reservoirs at high temperature andsalinity condition, considering 24 hours of placement, and 8 weeks ofpermanence, to finally degrade.

The composition of the disclosure can be used where is compatibilitywith the congenital water of the carbonated naturally fracturereservoir, in addition, it also woks properly where a productionassurance or improved oil recovery process is carried out and can besupplied through an injector producer well (FIG. 20).

For the development processing of the disclosure the following procedurewas followed: 1) evaluation of the stability of the gelling formulationat temperature conditions 120° C.; 2) characterization of the gellingformulation: a) Measurement of the viscosity (21° C.), and b)Determination of the Rheological Model of the gelling formulation ataverage reservoir condition, pressure 2,000 psi and temperature 120° C.;and 3). Monitoring the progress of cross linking and permanence of thegelling formulation at 30° C. and atmospheric pressure, usingrheological tests.

EXAMPLES

Some examples are given below of the application of organic gelformulations composition for blocking of fluids in carbonated naturallyfracture reservoirs, in accordance with the disclosure, it beingunderstood that said examples are illustrative only and are not intendedto limit the scope of the disclosure.

-   1) Evaluation of the stability gellant formulation at 120° C. The    evaluation of the stability gelling formulation consisted in    evaluating different chemical products based on polyacrylamides in    an air convention oven at a temperature of 120° C. and using the    code development by Robert Sydanks in 1988, to evaluate the    qualitative variation of the behavior of the apparent viscosity.

Example 1. In a 100 ml flask equipped with a magnetic stirrer, it isdiluted at room temperature and atmospheric pressure, 0.3% weight ofcopolymer of acrylamide butyl tertiary sulfonic acid (ATBS) andacrylamide, 0.12% weight of phenol and 0.18% weight ofhexamethylenetetramine in 99.4% weight of reservoir brine with a totalsolids content of 31,870.50 ppm. The FIG. 1 shows, the behavior of thecode developed by R. Sydanks (1988), of the aforementioned formulationat 120° C. as a function of time, prepared with brine at 0.3% weight ofthe polyacrylamide described above, 0.12% weight of phenol and 0.18%weight of hexamethylenetetramine, it is observed that the formation ofgel begins at 24 hours maintaining its maximum rigidity for 648 hoursand from this moment the degradation of the gel begins.

According to the table of resistance to the inversion movement in aglass tube, development by Robert Sydanks in 1988, Table 1, itqualitatively indicates the change in the resistance to movement of thegel in a fraction time.

In FIG. 1. It shows the advance in the gel strength of the formulationdescribed as a function time, for 22 hours the Sydanks code is 1,indicating that the solution has the same apparently viscosity(fluidity) as the polymeric solution, Increasing from 24 hours to 3, itindicates a detectable gel that flows to the surface of the containerunder immersion. After 144 hours, the Sydanks code is increased fromcode 3 to code 8 in 192 hours. The code 8 indicate the formation of aslightly deformable gel. After this time and up to approximately 648hours, the code 8 is maintained. Finally, the degradation starts fromthis moment, as shown in FIG. 11.

Example 2. In a 100 ml bottle equipped with a magnetic stirrer, 1.0%weight of sulfonic acid copolymer of tertiary butyl acrylamide (ATBS)and acrylamide, 0.4% weight of phenol and 0.6% weight ofhexamethylenetetramine diluted at room temperature and atmosphericpressure, in 98 weight of reservoir brine with a total solids content of31,870.50 ppm. In FIG. 2, the behavior of the code developed by Synanks(1988) of the aforementioned formulation at 120° C. as a function oftime is shown; this is prepared with 1.0% by weight brine of thepolyacrylamide described above, 0.4% weight of phenol. and at 0.6%weight of the hexamethylenetetramine, it is observed that the formationof the gel begins at 24 hours and maintaining its maximum rigidityduring 672 hours and is from this moment starts the degradation of thegel.

According to the table of the investment resistance of movement in theglass tube, developed by Robert Sydanks in 1988, Table 1. Indicates thequalitative way to change the resistance movement of the gel in fractiontime.

In FIG. 2, the advance of the gel of resistance of the formulation isshown, previously described as a function of time, during the first 24hours, the code of Sydanks is 8, which indicates the formation of aslightly deformable gel and after of 96 hours the code is 10, thisindicates The formation gel is rigid. At this time, the degradationbegins as shown in FIG. 16.

-   2) Characterization of the Gel Formulation.-   a) Viscosity measurement (21° C.). The viscosity was determined in    the FANN 35A viscometer for the formulation described in example 1    and example 2, which is described in example 3 and example 4.

Example 3. For the development of the measurement of viscosity asolution was prepared as described in Example 1, the results obtainedare shown in FIG. 3, which shows the behavior of the viscosity withrespect to the shear rate for the formulation of example 1, in FIG. 4,the behavior of the shear stress with respect to the shear rate for theformulation of example 1 at 21° C. is presented, after the analysis ofthe results it was obtained that at room temperature it behaves asPseudoplastic fluid or ShearThinning, this indicates that when this kindof fluid is subjected to shear stress, a variation of the viscosity iscaused. The stronger the effort, the higher its viscosity to the pointwhere the fluid offers great resistance to movement.

Example 4. For the development of the measurement of viscosity asolution was prepared as described in Example 2, the results obtainedare shown in FIG. 5, which shows the behavior of the viscosity withrespect to the shear rate for the formulation of example 2, in FIG. 6,the behavior of the shear stress with respect to the shear rate for theformulation of example 1 at 21° C. is presented, after the analysis ofthe results it was obtained that at room temperature it behaves asPseudoplastic fluid or ShearThinning, this indicates that when this kindof fluid is subjected to shear stress, a variation of the viscosity iscaused. The stronger the effort, the higher its viscosity to the pointwhere the fluid offers great resistance to movement.

TABLE 1 Description of the resistance to investment movement developedby Robert Sydaks, (X). Code Equivalent Definition Description A 1 Nodetectable gel The gel appears to have the same viscosity (fluidity) asformed the original polymer solution and no gel is visually detectable.B 2 Highly flowing gel The gel appears to be only slightly more viscous(less fluid) than the initial polymer solution. C 3 Flowing gel Most ofthe obviously detectable gel flows to the bottle cap upon inversion. D 4Moderately flowing Only a small portion (about 5 to 12%) of the gel doesnot gel readily flow to the bottle cap upon inversion usuallycharacterized as a tonguing gel (i.e., after hanging out of jar, gel canbe made to flow back into bottle by slowly turning bottle upright). E 5Barely flowing gel The gel can barely flow to the bottle cap and/or asignificant portion (>15%) of the gel does not flow upon inversion. F 6Highly deformable The gel does not flow to the bottle cap uponinversion. not flowing gel G 7 Moderately The gel flows about half waydown the bottle upon deformable not inversion. flowing gel H 8 Slightlydeformable The gel surface only slightly deforms upon inversion. notflowing gel. I 9 Rigid gel There is no gel-surface deformation uponinversion J 10 Ringing rigid gel A tuning-fork-like mechanical vibrationcan be felt after tapping the bottle.

b) Rheological model determination for example 1 at average reservoirconditions, pressure 2000 psi and temperature 120° C. The gelatoinjection system at average reservoir condition: 120° C. and 2000 psi,for application as fluid blockage is shown in FIG. 7 (Diagram of theviscosity measuring equipment for the determination of the rheologicalmodel), which consists of two cylinders of stainless steel with acapacity of 1,000 ml. this stores the solution gel to be used andanother gellant used solution, and a stainless steel capillary, whichhas the following instrumentation: A) Differential pressure sensor, B)Pressure sensors, C) Temperature sensor and D) Computer for dataanalysis.

In this way, the gel injection procedure is as follows: A) Prepare thegel solution and fill the storage cylinder, B) Bring the system to theexperimental temperature and monitor it by use of the temperaturesensor, C) Opening of the sensor valves, which determines thedifferential pressure, D) Injection of the gelling formulation for thefilling the lines, controlling the system with the pressurized pump, E)Determine the parameters (differential pressure, cutting force, cuttingspeed and Newtonian viscosity) necessary for the determination of therheological model.

Example 5. Determination of the rheological model of the gallantformulation described in example 1. The shear rate intervals at whichthe experimental viscosity measurements were made from 10 to 70 (1/s),the rate from which were obtained the differentials pressure and shearrate are show in table 2, with the experimental data proceeds to thedetermination of the rheological model. For the case of the behavior ofthis fluid, it is observed that it has a behavior as a pseudoplasticfluid, for which the experimental data was adjusted to a power lawmethod. With the equation shown in FIG. 8, it is possible to calculatedata that were not obtained experimentally, it is worth mentioning thatthis equation is valid only for a set shear rate, for this particularcase from 10 to 70 [1/s], below or above this interval another viscosityequation must be obtained. In FIG. 9, the q and K parameters of thepower law model are observed, adjusting the experimental values.

Example 6. Determination of the rheological model of the gellantformulation described in example 1. The shear rate intervals at whichthe experimental viscosity measurements were made from 600 to 1,000[1/s], the rate from which were obtained the differentials pressure andshear rate are shown in Table 3, with the experimental data proceeds tothe determination of the rheological model. For the case of the behaviorof this fluid, it is observed that it has a behavior as a pseudoplasticfluid, for which the experimental data was adjusted to a power lawmethod. With the equation shown in FIG. 9, it is possible to calculatedata that were not obtained experimentally, it is worth mentioning thatthis equation is valid only for a set shear rate, for this particularcase from 600 to 1,000 [1/s], below or above this interval anotherviscosity equation must be obtained. In FIG. 9, the η and K parametersof the power law model are observed, adjusting the experimental values.

TABLE 2 Differential experimental pressure at shear rate from 10 to 70(1/s) for determination of the rheological model Differential ShearShear Rate Pressure rate stress Viscosity Q[cm³/h] ΔP [bar] γ[1/s] τ[Pa]η [cP] 10 0.5372 10.0665 1.0164 100.9718 20 1.3205 20.0293 2.6019124.7289 30 1.8534 30.0439 3.5065 116.7137 40 1.5337 40.0586 2.901772.4364 50 1.5821 50.0214 2.9932 59.8376 60 1.9899 59.9841 3.764862.7629 70 1.8229 70.0506 3.4489 49.2340

-   3) Monitoring of the Crosslinking and Permanence of the Gelling    Formulation at 30° C. and Atmospheric Pressure, by Rheological    Tests.

The analysis of the flow curve, viscosity curve, Damping Factor, elasticmodulus and viscous modulus in Anton Paar rheometer model MCR501 atdifferent dwell times, analyzed with the concentric cylinder geometry,50 mm diameter parallel plate and Hollow Cylinder at 30° C., atmosphericpressure and shear rate (1/s): 0.1-1,000.

Example 7. To determine the flow curve, a gel solution was prepared asdescribed in Example 1, the results obtained are shown in FIG. 10 (Flowcurves at different residence times of the formulation described inExample 1), when observing the graph of the shear stress with respect tothe shear rate, we have a fluid with pseudoplastic behavior. Example 8.To determine the viscosity curve, a gel solution was prepared asdescribed in Example 1, the results obtained are shown in FIG. 11(Viscosity curves at different residence times of the formulationdescribed in Example 1), when observing the different viscosity curves,it dependents on the shear stress in different residence times of thegel sample, this is a pseudoplastic behavior, indicated that thismaterial is submitted to the shear rate and decrease viscosity.

TABLE 3 Differential experimental pressure at shear rate from 600 to1000 (1/s) for determination of the rheological model. DifferentialShear Shear Rate Pressure rate stress Viscosity Q[cm³/h] ΔP [bar] γ[1/s]τ[Pa] η [cP] 600 2.3571 622.6724 4.4595 7.1618 715 2.9678 742.01805.6149 7.5670 800 3.2325 830.2299 6.1156 7.3662 900 3.5167 934.00866.6533 7.1234 1000 3.2827 1037.7874 6.2105 5.9844

Example 9. To determine the modulus of elasticity or also known asstorage modulus [G′], which indicates how much deformation energy isstored during a cutting process, a gel solution was prepared asdescribed in Example 1, The results obtained are shown in FIG. 12 (Graphof the elastic modulus as a function of time for the formulationdescribed in Example 1), observing the increase of the elastic modulusin time according to the scheme of residence time required for this gel.

Example 10. To determine the viscous modulus or also known as the lossmodulus [G′], which indicates the energy of deformation used by thesample during and after a shear or stressing process, a gel solution wasprepared as described in example 1, the results are shown in FIG. 13(Graphs of the Viscoso Modulus versus the time for the formulation ofExample 1), it is observed how the energy of the sample is exhausted bythe change of its structure until the time of 648 hours

Example 11. The damping factor relates the viscous behavior [G′] and theelastic behavior [G′] is defined as the tan δ=G″/G′, if the quotient ofthe modulus is <1 the character the material is considered a gel, if thequotient of the modulus >1 the character the material is liquid and ifthe quotient of the modulus is =0 this is at its gel point. For thedetermination of the Damping factor a solution described in example 1 isprepared, the results obtained are show in FIG. 14 (plot of the Dampingfactor versus the time of formulation of example 1), which indicatesthat it is a material with GEL character since the ratio of the elasticmodulus is greater in relation to the viscous modulus.

Example 12. To determine the flow curve, a gellant solution was preparedas described in Example 2, the results obtained are shown in FIG. 15(Flow curves at different residence times of the formulation describedin Example 2), when observing the graph of the shear stress with respectto the shear rate, we have a fluid with pseudoplastic behavior.

Example 13. For the determination of the viscosity curve a solution wasprepared as described in example 2, the results obtained are shown inFIG. 16 (Viscosity curves at different residence times of theformulation of example 2), observing the different viscosity curvesdependent on the shear stress at different dwell times of the GELsample, this presents a pseudoplastic behavior, indicating that when thematerial is subjected to a shearing stress, its viscosity decreases.

Example 14. For the determination of the elastic modulus a solutiondescribed in Example 2 was prepared, the results obtained are shown inFIG. 17 (Graph of the Elastic Modulus versus time for the formulation ofExample 2).

Example 15. For the determination of the viscous modulus, a solutiondescribed in Example 2 was prepared, the results obtained are shown inFIG. 18 (Graph of the Viscose Modulus versus time for the formulation ofExample 2).

Example 16. For the determination of the Damping Factor a solutiondescribed in Example 2 was prepared, the results obtained are shown inFIG. 19 (Graph of the Damping Factor versus time of the formulation ofExample 2), which indicates that it is a material with GEL charactersince the ratio of the elastic modulus is greater in relation to theviscous modulus. However, a maximum increase in the Damping factor isobserved at the time of 672 hours which indicates a degradation of thematerial as it behaves more and more like a liquid than an elasticmaterial.

Example 17. According to the table of resistance to the inversionmovement in a glass tube, developed by Robert Sydanks in 1988, Table 1,the change in the resistance to movement of the gel in a fraction oftime is qualitatively indicated.

In FIG. 20, It shows the advance in gel strength of the formulationdescribed in Example 1 and Example 2 as a function of time for twowaters with different salinities. The first water, called congenitalwater, contains a higher hardness content such as calcium carbonate ofapproximately 7.283 ppm, a low sulphate value, approximately 240 ppm, achloride content of 19.343 ppm and a pH of 6.61. While for the watercalled Water Sea, the hardness content reaches only 1,022 ppm, asignificant content of sulfates with 3,058 ppm, a content of chloridesof 18,018 ppm and its pH is 8.1. All these variations of the content ofcations and anions, provide for the case of the formulations developedin the example 1 and 2, a slight increase in its code of resistance tomovement according to the methodology developed by R. Sydanks in 1988for when they are formulated in the water called Water Sea, which withwater called congenital water.

REFERENCES

(1) Lockhart, T. P., SPE, paper 20998, 1991.

(2) Seright, R. S., SPE; paper 80200, 2003.

(3) Simjoo, M., SPE; paper 122280, 2009.

(4) Moradi-Araghi, A., Doe, P.H., SPE, paper 13033, 1984.

(5) Moradi-Araghi, A., Doe, P, SPEREJ 2 (2), 1987.

(6) Moradi-Araghi, A., SPE,paper 27826, 1994.

(7) Hardy, M. B., Botermans, C. W., Hamouda, A., Valda, J., John, W.,SPE, paper 50738, 1999.

(8) Albonico, P., SPE, paper 28983, 1995.

(9) R. D. Sydansk, R. D.; SPE/COE 17329, 1988.

The invention claimed is:
 1. A composition of organic gel formulationswith improved stability, which is configured to isolate an area of anaturally fractured carbonated reservoir, the composition comprising:0.3 to 1% by weight of a copolymer of acrylamide butyl tertiary ofsulfonic acid and acrylamide; and 0.12 to 0.4% by weight of phenol andfrom 0.18 to 0.6% by weight of hexamethylenetetramine; wherein theorganic gel formulation comprises a colloidal system having a solidcontinuous phase and a dispersed liquid phase formed over a period of atleast about 20 hours to provide temporary isolation of the area of thenaturally fractured carbonated reservoir.
 2. The composition of claim 1,wherein the colloidal system having the solid continuous phase and thedispersed liquid phase is formed over a period of about 24 hours.
 3. Thecomposition of claim 1, wherein the colloidal system having the solidcontinuous phase and the dispersed liquid phase is formed at atemperature of about 120° C.
 4. The composition of claim 1, wherein thecolloidal system having the solid continuous phase and the dispersedliquid phase maintains a maximum rigidity for up to about 648 hours andcommences degradation thereafter.
 5. The composition of claim 1, whereinthe colloidal system having the solid continuous phase and the dispersedliquid phase maintains a maximum rigidity for up to about 672 hours andcommences degradation thereafter.
 6. The composition of claim 1, whereinthe colloidal system having the solid continuous phase and the dispersedliquid phase maintains a maximum rigidity for at least about 96 hoursand commences degradation thereafter.
 7. The composition of claim 1,wherein the colloidal system having the solid continuous phase and thedispersed liquid phase acts as a fluid reservoir for blocking fluid flowfrom the isolated area of naturally fractured carbonated reservoir at atemperature of up to about 120° C. and a pressure of up to about 2000psi.
 8. The composition of claim 1, wherein the colloidal system havingthe solid continuous phase and the dispersed liquid phase acts as afluid reservoir for blocking fluid flow from the isolated area ofnaturally fractured carbonated reservoir at a temperature of up to about120° C. and a fluid salinity of up to about 31,870 ppm.